WASHINGTON (Reuters) - The U.S. Senate will vote this year on a proposed constitutional amendment that would let states and Congress regulate campaign finance laws, Senator Chuck Schumer said on Wednesday.

The New York Democrat made the announcement weeks after a ruling on April 2 by the U.S. Supreme Court striking down aggregate campaign donation limits, a decision that could allow wealthy individuals to contribute even more to candidates and party committees.

The proposed constitutional amendment, written by New Mexico Democrat Tom Udall, would empower Congress to regulate federal election spending and outside groups, and give states the chance to dictate their own internal campaign finance rules.

"The First Amendment is sacred, but the First Amendment is not absolute. By making it absolute, you make it less sacred to most Americans. We have to bring some balance to our political system," Schumer said at a Senate Rules Committee hearing that also featured testimony from former Supreme Court Justice John Paul Stevens.

Democrats generally decry the injection of large sums of money into politics, particularly since the 2010 Supreme Court decision in Citizens United v Federal Election Commission, which opened the door to so-called super PACs.

The proposed amendment is unlikely to pass the Senate in the highly partisan environment in the run-up to congressional elections in November. It would need 67 votes to pass and Republicans have generally supported loosening campaign finance restrictions, but it could give Democrats an opportunity to paint their rivals as opposing important reforms.

While Democrats have embraced high-profile donors of their own, they have made opposition to Republicans' reliance on billionaires such as Charles and David Koch a central plank of their election strategy.

(This story corrects the second paragraph to say party committees instead of political action committees)